Report CSS and JS coverage

[macbre]

https://github.com/puppeteer/puppeteer/blob/main/docs/api.md#class-coverage

Coverage gathers information about parts of JavaScript and CSS that were used by the page.

An example of using JavaScript and CSS coverage to get percentage of initially executed code:

// Enable both JavaScript and CSS coverage
await Promise.all([
  page.coverage.startJSCoverage(),
  page.coverage.startCSSCoverage()
]);
// Navigate to page
await page.goto('https://example.com');
// Disable both JavaScript and CSS coverage
const [jsCoverage, cssCoverage] = await Promise.all([
  page.coverage.stopJSCoverage(),
  page.coverage.stopCSSCoverage(),
]);
let totalBytes = 0;
let usedBytes = 0;
const coverage = [...jsCoverage, ...cssCoverage];
for (const entry of coverage) {
  totalBytes += entry.text.length;
  for (const range of entry.ranges)
    usedBytes += range.end - range.start - 1;
}
console.log(`Bytes used: ${usedBytes / totalBytes * 100}%`);

[gmetais]

Amazing 😮